Composite-metal valve tappet



Dec. 24, 1929. G. R. RICH 1,740,666

COMPOSITE METAL VALVE TAPPET Original Filed Oct. 8, 1927 a ilulllllll 6 man 45 that was placed Patented Dec. 24, 1929 UNITED STATES PATENT OFFICE GEORGE E. RICH, OF- BATTLE CREEK, MICHIGAN, ASSIGNORP TO WILCOX-RICH OCR- PORATION, F DETROIT, MICHIGAN, A' CORPORATION OF' MICHIGAN COMPOSITE-METAL VALVE TAPPE'I Original application filed. October 8, 1927, Serial No.

224,999. Divided and this application filed October 31, 1928; SeriaIlNo, 316,335;

metal articles of manufacture, comprising a hollow steel'shank or stemportion having a head thereon, formediwith a cast 1ron or white 11'011 surface portlon. One of the obgects ofthe present invention is the produc- 15 tion'ofhollow tappetst andanalogous metal articles composed of a hollow steel shankand an iron-canrcontactingisurface portion integra'llyv united in aihomogenous mass: Another object is theproduction of composite metal :articles ofmanufacture composed of a hollow, steel shank'iand head having a white iron facing, integrally united with the. head so asxto. form a homogeneous mass:

The desirabilitylof forming. a valve .tappet Z5 withia CilSUlIOHIOI white iron cam contacting surface'is well recognized, and l have heretofore produced tappets of this type, of which one is shown andv described in my' prior United States Patent No:1,628,911 dated May 17-, 1927 Therdesirability ofa hollow tappet havinga shanlr formedwith =a veryv thin wall or shell is apparent, but considerable difficulty has been encoun'teredin attempting to fuse cast iron'to the head portion of a hollow tappet becauseofthe difliculty in holdingthe cast: iron over the hole inthe tappet while in a moltenstate. In the manufacture of steel tappets having acast'iron or white: iron cam contactingsurfaceportion, an electric are 40 welding "process is usually used'for melting the cast ironand fusing it to the steel head portion of the tappet, and because of the: eX- ceedingly hightemperature used in the fusing process, it wastfound that any material in the hollow portion'of the tappet' for the purpose of supporting the moltenmetal would meltiduringthe welding process andpermit the molten cast iron.:to escape through "the hollow tappet.

Inaccordancewith the present invention,

I placea castiron plug in the end of the hollow tappetand support the plug therein, so that it willnot fall therethrough by gravity, and then heat the plug with an arc welding tool or other suitable heating element and me tthe upper portion of the plug, permitting the meltedportion to flow upon the top surface: of the steel tappet head, and continue the application of the heat for a sufficient length of time to convert the upper part of the cast iron plug'intowiiite iron andfuse or weld the same to the steel tappet head without, how ever, meltingthe lower end of the plug, and, in this manner, I anr able to prevent the molten metal from'flowing through the hollow of the-tappet. The invention consists, therefore, in a composite metal article of manufacture,- such as avalve tappet or poppet valve, having a-hollow thin shelled steel shank and head portiomand a cast iron or white ironsurface-portion welded to the head portion @of'the tappetl It further cons-istsin acomposite metal article of'manufac-ture in which the surface portion (initially composedof a cast iron plug) hasbeen converted into white iron, welded to the head portion of a hollow valve tappet 'oranalogous article. It further consists in the several novel features hereinafter fully setforth and claimed.

Theinventionds clearly illustrated in the drawingaccompanying this specification, in which.

Eigure-l'is a-central longitudinal section taken-through a composite metal-valve tappet and illustrating a simple embodiment of the present invention;

Fig. 2 is aside elevation of'one form of cast iron plug used in forming the composite metal tappet Fig; 3 is a View, partly in side elevation and partly in central longitudinal section, of the steel shank and head portion of the tappet' and showing this part of the tappet as it appears before the cam contacting surface has been welded thereto;

Fig.4 is aiview, partly in side elevation and partly in central longitudinal section, of the hollow steel shank and headportion and thezcast iron plug assembled and showing the same held in a support during the welding operation;

Fig. 5 is an end view of the finished tappet seen in Fig. 1;

Fig. 6 is an end View of the steel tappet piece seen in Fig. 3 and Fig. 7 is an end view, looking from below, of the castiron plug seen in Fig. 2.

Referring to said drawing, and first to Fig. 1, which illustrates a completed valve tappet made in accordance with the present invention, the reference character 8 designates a thin shelled, hollow steel shank, which may be formed at one end with a thickened wall containing internal screw threads 9 for the reception of an adjustment stud as is customary, or it may be formed in any other desirable manner for engagement with the stem of a poppet valve or other device which is intended to be actuated by the tappet. On the other end of the hollow steel shank 8 is formed a steel head portion 10, to which is fused the cam contacting surface portion 11, which is composed of iron, and, as a preference, is composed of white iron, integrally united with the steel head portion 10 of the tappet.

In the finished tappet, the white iron car contacting surface portion takes the form ofa disk like part 12 which overlies the steel head portion 10 of the tappet and is integrally united therewith, the white iron portion of the disk being thickened at its middle portion as shown at 13 in Fig. 1, below which is a portion l l which has not been converted from cast iron into white iron, but retains its original condition. It will be noted from the cross hatching appearing in Fig. 1, that the white iron disk like part 12 and part of the thickened portion 13 of the cam contacting surface portion of the tappet are integrally united with the steel tappet head, whereas the lower part 1 1 of the plug has not been melted, but remains in its original condition.

A composite metal valve tappet embodying the present invention is preferably constructed in the following manner. A steel blank for the shank and head portion (having a shape substantially as shown in Fig. 3) is first formed with suitable dies. It is 7 then bored out from the head end to form the thin shelled hollow shank 8, having the relatively thick wall at the end opposite the head, and the end face of the head piece 10 is preferably machined to provide a depression 15 surrounded by a marginal rim 16. To provide a support for the cast iron plug 11 during the welding operation, the bore is enlarged at the head to provide a shoulder 17 below the head. The cast iron plug 11, preferably is formed with a disk like head part 12 and a short stem or neck 14, the stem or neck being of sufficient length to engage the shoulder 17 when assembled with the steel body portion of the tappet. The amount of metal in the disk portion 12 is calculated to completely fill the recess or depression 15 when melted.

After the-pieces have been formed, the cast iron plugs are assembled with the steel pieces and the assembled pieces placed in a metal plate 18 (see Fig. 4:) which forms one terminal of an electric arc welding circuit. The plate 18 contains a number of holes (one of which is shown in Fig. 4) through which the shank of the tappet extends and above the holes the upper face of the plate is recessed to form cavities, one of which is shown at 19, for receiving the head portion of the tappet. In actual practice a large number of tappets are placed in the plate-18 at a time, and the workman applies the arc welding tool to the plugs of the several tappets in succession. The arc welding tool is held upon the plug 11" until the metal thereof melts and flows out into the surrounding portion of the recess 15, and the tool is applied for a sufficient length of time to fuse the metal of the disk like portion 12 of the plug to the steel head of the tappet piece, this length of time being sufficient to convert the cast iron into white iron. When melted, the disk like part 12 usually assumes crowned like appearance, as is illustrated by the dotted line 11 in Fig. 4.

t It has been found that by properly gauging the length of time for applying the arc welding tool to the parts, that fused with the steel head portion 10, although the lower end 14 of the plug (see Fig. 4) is not fused, but remains seated upon the shoulder 17 thereby forming a closure for the hole in the shank for retaining the molten portion of the plug above it. In actual practice, the plate 18 and the shanks of the tappets are water cooled during the welding process, whereby the intense heat (to which the tappets are subjected) is rapidly conducted away from the tappets, which makes it possible to employ the lower portion of the cast iron plug as a closure for preventing the molten portion of the plug from flowing down through the hollow of the tappet shank.

It is understood that after the tappet has been formed as above described, the crowned white iron surface portion of the head is ground down to provide the desired cam contacting surface, and the remainder of the tappet is machined and finished as is well understood.

From the above it will be apparent that the iron cam contacting surface portion of the tappet is fused to the head portion despite the fact that the shank portion of the tappet is hollow at the time the iron portion is welded to the head. Furthermore, in a hollow tappet composed of a steel body and an iron cam contactingsurface portion welded the upper orcrowned portion of the plug is completely thereto, the shell or wall of the shank may be made very thin, although sufficient metal may be left in the shell or wall at the end opposite the head for receiving the threads for the adjustment stud.

More or less variation of the exact details of construction is possible without departing from the spirit of this invention. I desire, therefore, not to limit myself to the exact form of the contruction shown and described, but intend, in the following claims, to point out all of the invention disclosed herein.

I claim as new, and desire to secure by Letters Patent:

1. A composite metal article of manufacture comprising a thin shelled hollow steel shank having a steel head portion on one end and a relatively thick internally threaded wall at its other end, and a cast iron plug contained in the hollow of the headed end of said shank and having an iron portion extending over said steel head portion and integrally united therewith.

2. A composite metal valve tappet com prising a hollow thin shelled steel shank formed with a steel head portion at one end and a relatively thick internally threaded wall at its other end, and there being an internal shoulder in the hollow of the shank, below said head portion, and a cast iron plug contained in the hollow of the shank and contacting with said shoulder, the upper part of said plug being composed of white iron and overlying said steel head and integrally united therewith.

GEORGE E. RICH. 

